Photosensitive Unit Alignment via Pressing Force
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Solution Overview
Problem
In image forming apparatuses, the photosensitive member unit may displace in the width direction during movement along the placement path due to clearance between the main body and the photosensitive member unit, leading to misalignment with the sheet conveying path, which can result in deteriorated image quality.
Innovation Solution
The apparatus incorporates main body-side electrodes that apply a pressing force to the photosensitive member unit, guiding it to maintain alignment with the sheet conveying path by using guide surfaces and positioning protrusions, ensuring accurate positioning and reducing displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the photosensitive member unit moves along the placement path between removable position and operational position, then the photosensitive member unit can be attached or detached for maintenance and replacement, but widthwise clearance between the main body and the photosensitive member unit causes displacement in the width direction, leading to misalignment with the sheet conveying path and deteriorated image quality
Solution Approach 1:
The pressing arm is pre-configured to press the positioning shaft toward the contact surface before the photosensitive member unit is fully inserted. This preliminary action ensures that as the unit moves along the placement path, the positioning shaft maintains continuous contact with the contact surface, preventing widthwise displacement and ensuring accurate alignment from the outset
Solution Approach 2:
The positioning shaft acts as an intermediary element between the photosensitive member unit and the main body. It transmits the pressing force from the pressing arm to the contact surface, mediating the interaction to maintain precise positioning while allowing the unit to be detachable for maintenance
2Productivity
If the force transmitting device engages the force receiving device to transmit drive force, then the photosensitive member unit can be driven in the operational position, but pressing force from the force transmitting device may cause displacement in the width direction or opposite direction, leading to misalignment and deteriorated image quality
Solution Approach 1:
The pressing arm applies a counteracting pressing force to the positioning shaft in the width direction before and during the engagement of the force transmitting device. This preliminary anti-action prevents the pressing force from the force transmitting device from causing displacement, thereby maintaining alignment accuracy while still enabling effective drive force transmission
Data Source
AI summary
An electrophotographic image forming apparatus may include a main body including a reference protrusion having a reference surface on one side and a pressing member on the other side, and a photosensitive member unit configured to move between an operational position and an outer position. The photosensitive member unit stops at a particular position located between the outer position and the operational position. The reference surface of the main body may contact the photosensitive member unit located in the operational position. The pressing device of the main body may be configured to press the photosensitive member unit toward the reference surface when the photosensitive member unit is located in the particular position and in the operational position.